What was the best pitching season ever? We could look at the lowest ERA, but in some eras, ERAs were naturally low, like in the deadball era before 1920 when there were many seasons with ERAs under 2.00. We could look at the seasons with the most wins or highest winning percentages, but those are determined not just by the quality of the pitching but also by the run support a pitcher gets.

We could get around this problem by comparing a pitcher's ERA to the league average. Two pitchers might be judged equal if their ERAs are both 25% below the league average. Pitcher A might have an ERA of 3.00 with the league average being 4.00 while pitcher B has an ERA of 2.25 in a league with an average ERA of 3.00.

But a problem that often emerges in this approach is that the best seasons often come when runs per game were very high or very low. In extremely high scoring seasons, it may be easier to go far below the league average since the average is so high. Extremely low scoring seasons might increase the chances of any pitcher having a very low ERA.

One possible solution is to compare the best pitcher in the league to the other good pitchers in the league. If it is easy for one pitcher to go far below the league average, it should be easy for a few others. By comparing the league leader in ERA (or any measure of pitching quality) to the other very good pitchers, the problem mentioned above might be lessened.

ERA can also be affected by the home ballpark of the pitcher. So in addition to comparing the best pitchers to other good pitchers, their performance should be adjusted for park effects. Pitchers in high scoring parks will have their runs allowed adjusted downward and vice versa.

One measure that allows for this is called RSAA. It comes from the Lee Sinins Sabermetric Encyclopedia, a commercial database that can be purchased by any baseball fan. Here is the definition: "Runs saved against average. It's the amount of runs that a pitcher saved vs. what an average pitcher would have allowed."

I looked at how the RSAA of league leaders since 1900 compared to the average RSAA of the pitchers who finished 2-10 (hence, the idea of comparing top pitchers to other good pitchers). For example, Walter Johnson had 75 RSAA, meaning he allowed 75 runs less than the average pitcher. The next 9 best pitchers in 1913 averaged 25.56. So Johnson was 49.44 better.

But having, say, 30 more RSAA than the next best nine pitchers might mean more in a low scoring year than a high scoring year. In a low scoring year it will take a lower number of runs to add one over the course of a season. But how many? I used the formula which says it takes 10 times the square root of the number of runs scored per inning by both teams (found in Total Baseball, 5e). If each team scores .5 runs per inning, the total is one. The square root is 1 and 10 times that is 10, so it would take 10 additional runs over the course of a season to win one more game. The Lee Sinins Sabermetric Encyclopedia can call up the top 10 each season in RSAA.

Who were the top pitchers according to this method? The top 10 in the AL are listed below:

In 1913 it took 9.39 runs to win one more game. Since 49.44/9.39 = 5.26, Johnson added 5.26 more wins than the average of the next best nine pitchers in the league (I have eleven pitchers here--Hal Newhouser's season was a war year, when many good pitchers may have been in the military).

One problem can be seen--if you know some baseball history--is that we still see the best pitching performances coming from what are generally fairly high or fairly low scoring years. I really don't know the solution. Comparing players using standard deviations instead of simple averages might be better. I ran this study and ranked pitchers in ERA based on how many standard deviations below the average of all qualifying pitchers they were. Pedro Martinez in 2000 was the best, being 3.79 SDs below average.

Looking at ERA has an advantage over RSAA, since it only includes earned runs whereas RSAA includes both earned and unearned runs. Unearned runs may not be the fault of the pitcher. I also looked at the best ERAs relative to the 2-5 pitchers each year.

But both RSAA and ERA are, in part, determined by the quality of the fielding behind the pitcher. In his Win Shares methodology, Bill James attempted to rate pitchers solely on their contribution to winning, independent of the fielders. Using the electronic Win Shares database, I found the best seasons by taking the league leader and seeing how many Win Shares he had as percentage of the pitchers who finished 2-5.

The same pitchers seem to be near the top on all of these lists (including the lists at the links given above). There could be a problem that the quality of pitchers they are being compared to is relatively low (which might explain why they all do so well in simple comparisons to the league average as well). Maybe some years just did not have many good pitchers. I don't know how that could be determined. One suspicion I have about some of Pedro Martinez's good years is that there were no other very good pitchers. Roger Clemens was in decline. Randy Johnson was traded to the NL. But maybe the same could be said about Bob Gibson in 1968. Sandy Koufax was gone. Tom Seaver had yet to hit his prime. Maybe it could be said about any of these pitchers.

Some pitchers who stand out even among this crowd are Walter Johnson, Grover Cleveland Alexander, Greg Maddux, and Pedro Martinez. They each have two consecutive seasons that both appear near the top of these lists. They proved what they did was no fluke.

Cyril Morong teaches economics at San Antonio College and is a lifelong White Sox fan. A member of SABR since 1995, his articles have appeared in The Baseball Resarch Journal, By the Numbers and on line at The Chicago Sports Review.

Comments

Great post. I would be curious to see, by measuring the same way, the best rotation in history or perhaps how those teams in those years did with one (or more) very, very good pitching seasons behind them.

Garth: Thanks. It might be worthwhile to look at the best pitching teams. But right now I don't have time.

Steve: Falkenberg's best RSAA after his 81 in 1914 is 27 in 1913 in the AL. Other than that, he was generally negaitve or very low. Maybe he would have done very well in the AL that year. We have seen some pitchers have one great year (can't think of any right now). In the new Baseball Encyclopedia, Pete Palmer gives the Federal League players something like 80% of their value when ranking them all-time. Even 80% of 81 would be a great year. I just have no idea how to figure this.

Where did you get an electronic Win Shares database. I've been looking all over trying to find one. Any info would be greatly appreciated!

Posted by: Chris at August 2, 2005 8:52 AM

You need to go to the STATS, INC website. It is actually called "Win Shares - Digital Edition" Go this site

http://www.stats.com/store/store.asp?page=wins

Posted by: Cyril Morong at August 2, 2005 9:42 AM

Thanks for your help - are those updated through 2004 or just 2002?

Posted by: Chris at August 7, 2005 4:07 PM

hello folks, A friend and I are having an ongoing discussion he says NOLAN RYAN is the best and I say he is among the top 15-or 20 ???Any input would be most welcome thanx charlie

Posted by: charlie at October 10, 2005 11:29 AM

Nolan Ryan is not number 1. Maybe top 20. As far as the stats of each particular era go, my best-remembered pitching performances would have to be Gooden's '85, Gibson's '68, Pedro's '99, Koufax's '65, and on a personal admiration level, Hersheiser's '88.

Posted by: Phil at November 30, 2005 1:20 PM

I'm wondering, would it possible for a No. 2 in a certain year be better than a No. 1 in another year?

Posted by: Max at December 19, 2005 11:26 PM

Yes, that would be possible. The best pitching seasons have typically been clumped together, particularly in the Deadball Era and in a year like 1968. However, this study is adjusting for such effects by analyzing the best pitching seasons relative to the league average as opposed to absolute terms.

I've always been convinced that Martinez's 2000 season was far and away the best pitched season ever. As you've shown very nicely, his numbers stack up with all the best pitched seasons, no matter how you adjust them (or even if you don't). Not only that, but he certainly received no aid from his home park or the mediocre defense behind him.
There's one stat for him that always stands out to me: his 0.74 WHIP. That season, Martinez allowed an absurdly low number of baserunners, an indication of his dominance. I believe I once read that only one other single-season WHIP of any pitcher, ever, even broke 0.80.

Why isn't Ron Guidry even mentioned for his 78 season? In my opinion, this whole article is slanted because of this omission. 25-3 record, ERA of 1.74, 9 shutouts, 250 K's, and MOST importantly, a world series ring!

Posted by: Bo Williamson at February 19, 2006 4:05 PM

Where is Koufax's 63 season?

Posted by: Bo Williamson at February 19, 2006 4:13 PM

Koufax in 1963 actually was second in the league to Dick Ellsworth. You have to remember that RSAA is park adjusted and Koufax pitched in a very good pitcher's park. Ellsworth pitched in Wrigley Field. Koufax had an ERA of 1.88 that year but Ellsworth is not too far behind at 2.10. He only beats Koufax in RSAA by a 43-40 margin.

You also have to remember that each league leader in RSAA is judged against the next best 9 pitchers for that season. Then even that is adjusted for how many runs it took that year to win one game. Koufax's 1966 season is 23rd among NL pitchers (2.89 wins better than pitchers 2-10-Koufax had 58 RSAA that year). Ellsworth's 1963 season is 57th.

Guidry's 1978 season was 35th among AL pitchers.

Here are the RSAA leaders in the 1963 NL and the 1978 AL. To make my list, a pitcher would have to really dominate the next best 9 guys. You have to put things in context.